1. Field of the Invention
The present invention relates generally to flexible piping, and in particular to insulated flexible piping with an inner flexible metal piping section and an outer insulating sleeve.
2. Description of the Related Art
Flexible piping is desirable in a variety of applications for handling fluids and bulk materials. For example, Thomas U.S. Pat. No. 5,228,479, which is assigned to a common assignee herewith, discloses multi-layered flexible piping and a method and machine for forming same. Examples of spiral-wound flexible metal piping date back at least as early as the 1930's, as exemplified by the Hungerford U.S. Pat. No. 1,913,390 for flexible metal tubing having a single layer construction. Such spiral-wound flexible metal piping or hose has previously been provided with insulated coverings. For example, the Busse U.S. Pat. No. 3,393,267 discloses a connector for jacketed strip-wound metal hose wherein a plastic electrical insulation material jacket is tightly fit over the exterior of spiral-wrapped metal hose.
The Lalikos et al. U.S. Pat. No. 4,854,416 discloses a convoluted conduit which is provided with a loosely-fitting outer braid sleeve or stocking for increasing pressure carrying capability, for providing an armor protection for an inner core and for controlling stiffness and resonant frequency for dampening vibration.
However, heretofore there has not been available insulated flexible metal piping with the advantages and features of the present invention.